1. Field of the Invention
This invention relates to indexing devices and in particular to indexing devices for locating an edge surface of an article positioned adjacent thereto.
2. Description of the Prior Art
The edge indicating probe or precision edge finder is used by machinists working on materials with a jig bore machine, a milling machine, or other similar machines having adjustable or movable tables. The edge indexing device allows the workpiece or article to be quickly secured to the adjustable table, with the table then being moved into communicaton with the indexing device so that the heretofore time consuming measurement and adjusting steps may be eliminated or drastically shortened. For example, the exact location of holes within a workpiece may be confirmed by measuring the distance between each of the holes and one or more reference edges. In this manner any location in the area defined by the workpiece may be accurately predetermined by a space relationship with respect to one or more regularly shaped edges of the workpiece.
An early precision edge finder is disclosed by Rizor in U.S. Pat. No. 2,435,799. The Rizor precision edge finder utilizes an L-shaped element which communicates with the upper and side edge surfaces of the workpiece, and an indicator which fits within an elevated centering block. While this precision edge finder may be used to accurately locate the edge of a stationary workpiece, the L-shaped element must be repositioned each time a different section of the edge of the workpiece is measured. Also, the Rizor edge finder is subject to visual measurement errors induced by the requirement for aligning the probe with the cross hairs.
Others indexing devices are disclosed by Janci, In U.S. Pat. No. 3,813,989, Farnsworth, in U.S. Pat. No. 3,090,633, Cross, in U.S. Pat. No. 3,048,059, and Papps et al, in U.S. Pat. No. 3,026,621.